The orthopaedic appliances used for the surgical manipulation of bones are of the type driven pneumatically, with compressed air or an electric motor. Electrically driven devices are powered both from the mains power supply and by battery.
In addition, surgical devices are generally multi-function in the sense that they can drive various surgical instruments, even though the type dedicated to performance of a single function exist, such as in the case of sawing bones, which entails driving characterised by a rectilinear, alternate movement, therefore not circular.
The intended use of such surgical appliances presumes compliance with extremely strict safety standards. In this context, it is easy to see that the functioning of the driving apparatus of surgical devices—also called “drivers” in the present invention—must not present any interruption during the surgical operation. This means that drivers with a relatively long lifespan must be provided: this is the reason for which such drivers are subject to stringent testing to reduce as far as possible—it not being possible to eliminate them completely—interruptions to functioning during surgery.
In addition, when batteries are used to power electric motor drivers, they must have an appropriate voltage and long life: classically, the lithium type is preferred.
In certain cases the driver of the surgical device must also guarantee the possibility of varying the speed of the instrument, depending on the requirements related to the type of operation.
Overall, these drivers must be as light, manageable and easy to use as possible: from this point of view, one may easily see that the ergonomic nature of the grip of the driver is practically obligatory.
Of course, the question of asepsis also concerns the surgical appliances fitted with instruments intended for general surgery.
Normally, two main solutions are essentially used to ensure asepsis. A first solution consists of making a driver, preferably of the electric motor type, bearing a fully waterproof casing, inside which the electric motor, the power supply battery of such motor and the electric connection cables are enclosed. After each operation, such driver with waterproof casing is subjected, of course jointly with the surgical instrument (or surgical instruments in the case in which various have been used during the operation), to sterilisation in an autoclave, so as to make it suitable for another operation. Such solution has the advantage of permitting repeated use in sterile conditions of the waterproof driver. However, this is very expensive since making the driver waterproof and sterilising it requires, on the one hand, the use of appropriate materials and, on the other, the use of a specific manufacturing procedure, factors which inevitably reflect on the final costs, necessarily high, of such type of driver.
In addition, the lifetime of the device is considerably reduced as a result of the thermal stress imposed on the driver and the components enclosed within the casing and despite the measures adopted for its realisation (these measures regard the quality and appropriate thickness of the plastic material which the casing is preferably made from). In any case, the reduced lifespan of a waterproof driver—and therefore the need to replace it frequently—contributes, together with the waterproofing of its casing and the sterilisation in an autoclave, to making the relative cost of such solution even higher.
A second solution is of the disposable, single-use type and entails using a driver destined for use only once, thereby eliminating the need to subject it to sterilisation in an autoclave. This enables the use of less expensive materials and components even though the once-only use of such driver ends up heavily influencing costs, in that a different driver must be used for every operation.
From the above, the fact that both the extreme solutions used in the prior art, that is to say of a reusable waterproof driver and of a disposable driver, share the disadvantage of high maintenance and/or running costs, clearly emerges.